October 21, 2006

When your’re inserting graphics or images with thin lines or structures in a video when editing in pal or ntsc formats, these often start to flicker when viewed on a normal tv screen.

This happens due to the fact that pal and ntsc broadcasts are transmitted in an interlaced way. This means that not 25/29.97 full progressive frames per second are transmitted, but instead 50/60 interlaced images per second are sent. Through this broadcast images are split up in two images which contain just every second line of the image (1 image upper frame first, 1 image lower frame first). When using images with thin lines or structures, the lines or structures get split up for the two images. This often produces flickered images when viewd on a tv screen.

To get rid of these flickered images, there’s an effect in Apple’s Final Cut Pro called Flicker Effect which blends and blurs the frames slightly, but kills the strange looking effect. Voilá.